1. Field of the Invention
The present invention relates to a crystalline powdery saccharide, its preparation and uses, more particularly, to a crystalline powdery saccharide obtained by crystallizing trehalose along with a different saccharide(s) crystallizable in the presence of trehalose, its preparation and uses in food products, cosmetics, and pharmaceuticals.
2. Description of the Prior Art
Trehalose, as disclosed in Japanese Patent Kokai No.213,283/95, can be directly produced from starch by contacting reducing partial starch hydrolysates, having glucose polymerization degrees of 3 or more and being obtained from starch as a material, with both a non-reducing saccharide-forming enzyme that forms non-reducing saccharides having a trehalose structure as an end unit, and a trehalose-releasing enzyme that releases the trehalose structure from such non-reducing saccharides. Conventional methods for producing trehalose from maltose as a material include, for example, a method using a maltose/trehalose converting enzyme as disclosed in Japanese Patent Kokai No. 170,977/95, and a method using maltose- and trehalose-phosphorylases as disclosed in Japanese Patent Kokai Nos. 216,695/83 and 131,182/96. These methods, however, are not yet perfect on the trehalose yield; the trehalose yield to the material starch and/or maltose is at most 50-90 w/w %, on a dry solid basis (d.s.b.), (throughout the present specification, the wording "w/w %" is abbreviated as "%", unless specified otherwise), and the produced trehalose usually contains glucose, maltose, maltotriose, maltotetraose, etc., as coexisting saccharides.
As disclosed in Japanese Patent Kokai Nos. 213,283/95 and 170,977/95, it is known that trehalose is relatively-easily crystallized but the coexisting saccharides are deemed to be hardly crystallizable because trehalose has a crystallization inhibitory activity to the saccharides. Therefore, in the trehalose production, high trehalose content solutions produced from starch and/or maltose are usually decolored and desalted for purification, and concentrated, followed by crystallizing trehalose by adding a trehalose seed to the concentrate, separating the resultant mixture to remove impurities, and collecting crystalline trehalose hydrate with a relatively-high purity. It was found, however, that powdery saccharides containing crystalline trehalose hydrate and coexisting saccharides have serious demerits that they easily adsorb moisture to be solidified and easily lose their fluidity or free-flowing ability.
In the case of using a separation process for removing coexisting saccharides, a relatively-high quality crystalline trehalose hydrate, with a relatively-low moisture absorbency and an extremely-high stability and handleability, can be obtained. However, molasses containing quantities of coexisting saccharides as by products are formed so that beneficial uses of the molasses have been desired. Regarding to this, the present applicant, as disclosed in European Patent Application No. 739986, had established a high trehalose content syrup, wherein the trehalose crystallization is effectively prevented, which can effectively utilize the above molasses. The use, however, is just for a convenient method. Intrinsically, highly required is to basically improve the property of powdery saccharides containing molasses comprising crystalline trehalose hydrate and coexisting saccharides, and to establish high quality powdery saccharides. It is also strongly required that a method for preparing molasses, comprising trehalose and quantities of coexisting saccharides, into stable powdery saccharides.